Cant work with ne5534 amp

Discussion in 'Microcontrollers, Programming and IoT' started by asaf123098, Aug 7, 2018.

  1. asaf123098

    asaf123098

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    Hi, i am trying to operate a bldc motor with an esc and send pwm values to the esc with an arduino, it works great until i try to run it (the esc) with a rf reciever (arduino connected to the tx), in a video i watched a good solution was to amp the signal with a ne5534 ic and connect it by this scheme:



    At 5:45.

    But when i connect the amp, it outputs nothing, i tried to run a led with it and it wont turn on.
    Thanks!!
     
    asaf123098, Aug 7, 2018
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  2. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Can you show us your schematic and give us a picture of your constructed circuit?
     
    (*steve*), Aug 7, 2018
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  3. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Is that your video or someone else's? It works on the video.
     
    (*steve*), Aug 7, 2018
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  4. asaf123098

    davenn Moderator

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    some one else's :)


     
    davenn, Aug 7, 2018
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  5. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I kinda thought so, but I asked the question since circuit diagrams and the construction details are visible in the video.

    ... And the original question was not something I felt I could guarantee I completely understood :)
     
    (*steve*), Aug 8, 2018
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  6. asaf123098

    asaf123098

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    asaf123098, Aug 8, 2018
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  7. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I'm going to be brutally honest. I don't currently have the time to be viewing a particular but of a video and comparing it to a poor photograph on an external site. If I remember, I may be able to get back to it in a couple of days.

    You can really help by posting the images here where I can quickly flip between them on my phone.

    I would recommend you look at the resource on taking photos because your image is a bit marginal.
     
    (*steve*), Aug 8, 2018
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  8. asaf123098

    asaf123098

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    Im sorry, here is media embeded, as for my picture, if its not clear enough ill try to take another picture when i get home.

    Here is a picture of the ne5534 pinout:
    [​IMG]

    Here is a picture of the desired scheme(from great scott's video):
    [​IMG]

    Here is the pictue of my implementation:
    [​IMG]

    As for the video, i couldn't find how to embed it, thanks.
     
    asaf123098, Aug 9, 2018
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  9. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    With the same circuit, if you move the orange jumper from pin 6 to pin 3 of the NE5534, what happens?
     
    (*steve*), Aug 9, 2018
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  10. asaf123098

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    The datasheet indicates that this device will not work within specs with a single ended 5V supply. The specs indicate you won't get any output voltage swing.

    I suggest you try another op amp, one that has rail to rail inputs and outputs and will work from a single ended 5V supply.

    Maybe that person in the video got extremely lucky.
     
    (*steve*), Aug 9, 2018
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  11. asaf123098

    73's de Edd

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    Sir asaf123098 . . . . .

    Down in the RED LED indicator area and the installed 10K series resistor . . . . . don't you think that is going to provide one hellishly LOW-LOW-LOW operating current even being available ?

    73's de Edd
     
    73's de Edd, Aug 9, 2018
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  12. asaf123098

    Audioguru

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    The designer of the circuit did not read the datasheet for the NE5534 op[amp he is using wrongly.

    The datasheet says the NE5534 opamp will not work when the supply is less than 6V but the video shows 5V.
    The datasheet also shows that the NE5534 will not work if the gain is less than 3. In the video and on your circuit it is too low at 1. In the video and on your tangled mess of wiring I do not see an important supply bypass capacitor.
    The output voltage of an NE5534 does not go high enough to light an LED when its supply is 6V but your supply is low enough to prevent the opamp from doing anything.
     
    Audioguru, Aug 9, 2018
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  13. asaf123098

    asaf123098

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    ok, so i am in a bit of a problem, when my RX is plugged into the motor's ESC, the pwm signal gets really low, what can i do about that? are there other amps that are better for low voltage use?
     
    asaf123098, Aug 11, 2018
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  14. asaf123098

    Audioguru

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    You need a high current digital buffer, not an opamp, but a digital buffer or an opamp will work only if we know the spec's it needs.
    There are many opamps that work using a 5V supply and a gain of 1 like in that circuit. But we do not know the details of the load that the opamp must drive:
    1) How high must the input voltage go? At what current?
    2) How low must the output voltage go? At what current?

    A Texas Instruments TLE2141 works with a supply as low as 4V so it works perfectly with a 5V supply. Its output goes to 4.1V with low current or 3.7V with 15mA. Its output also goes to 0.13V with low current or 1.7V with 15mA.
    But its inputs work only up to 3.0V with a 5V supply which might be fine or not in that circuit.
     
    Audioguru, Aug 11, 2018
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